Hi Keith i have never seen a disk so thick ,i was always told it should be a thin as for the nipkow hole side of things but seems to work very well .i wonder with the extra mass of the disk like this its acting like a fly wheel as well ,if it were possible it would be interesting to see the difference of something record thin and yours as to syncing if there would be any difference .Nice to see the set up in full .

The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.

Yes, Harry the disc is 6mm thick. Normally a laser cutter could not cut an aperture of 0.7mm x 0.5mm at this thickness with any useful accuaracy. Also the parallax would absolutely kill the image. I solved this by engraving ~5mm deep pockets into the acrylic before cutting the apertures. It has worked out really well. All the details are here. If you want a disc I will send you one.

Yes I was told the extra inertia will be bad but in fact it is good as it reduces motor cogging and increases speed stability. When you are using digital PI (Proportional Integral, derivative is not useful here) controllers there is plenty of control by tuning a few numbers. It is much easier to manage rotary loads these days. The only issue I have with the current motor control is the gearbox backlash. Once I go belt drive it should be rock solid I expect, and much quieter. I cant believe how rubbish a 40 something dollar motor from RS is.

CheersKeith

Last edited by Robonz on Thu Oct 12, 2017 1:05 am, edited 1 time in total.

Robonz wrote:Yes, Harry the disc is 6mm thick. Normally a laser cutter could not cut an aperture of 0.7mm x 0.5mm at this thickness with any useful accuaracy. Also the parallax would absolutely kill the image. I solved this by engraving ~5mm deep pockets into the acrylic before cutting the apertures. It has worked out really well. All the details are here. If you want a disc I will send you one.

I was wondering if you had counter sunk the holes ,great idea make the disk very stable no wobble to the disk and with those bearings spot on .I tend to use small disks at the moment Keith smaller the better i still like CD or dvd's ,i did learn my lessen with the last camera does not take much for it to wobble need to used a some thing better than the cd hub motor ,needs some thing like yours but i would use a video head or HD more stable for camera work easier for me to reuse .

Yes I was told the extra inertia will be bad but in fact it is good as it reduces motor cogging and add increases speed stability. When you are using digital PI (Proportional Integral, derivative is not useful here) controllers there is plenty of control by tuning a few numbers. It is much easier to manage rotary loads these days. The only issue I have with the current motor control is the gearbox backlash. Once I go belt drive it should be rock solid I expect, and much quieter. I cant believe how rubbish a 40 something dollar motor from RS is.

CheersKeith

[/quote]The fly wheel weight mass of that thing once it gets going the motor has little to do ! better off scrapping motors the ones in old u matic VCR's are great if you got a dud laying around very well made ,70's made great motors I can see you want to change the motor .

The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.

Cutting the pockets causes a small amount of warp in the acrylic. I do want to try annealing it in the oven to see what happens. I do have a spare disc to play with now too.

Yes, I do have an old VCR here for parts, but for now I like to try making all the bits myself. It adds to the mechanical challenge. I am designing new optics for my laser cutter to get the beam really exact so I can laser cut the hub directly. Hopefully It works! Right now if I laser cut hubs they wobble bad.

Seeing as I can make these Nipkow discs without a huge effort I have been considering making a double or even triple spiral to make the picture bigger. I have not seen many people do more than one spiral. Any advice or ideas on that? I do realise the speed has to double or triple. Getting rid of the magnifying glass with a large image would make it look really cool. Plus you get the nice drum behind the Nipkow disc.

Cutting the pockets causes a small amount of warp in the acrylic. I do want to try annealing it in the oven to see what happens. I do have a spare disc to play with now too.

Good to experiment and see this Nipkow made your way was new to me

Yes, I do have an old VCR here for parts, but for now I like to try making all the bits myself. It adds to the mechanical challenge. I am designing new optics for my laser cutter to get the beam really exact so I can laser cut the hub directly. Hopefully It works! Right now if I laser cut hubs they wobble bad.

With your laser cutting gear well worth it i am sort of suck with a drilling hot gluing re purpose what ever i have scrapped .

How small can you make a hole Keith out of interest if you know ? be very useful for higher line rates beyond manual drilling cnc drilling

Seeing as I can make these Nipkow discs without a huge effort I have been considering making a double or even triple spiral to make the picture bigger. I have not seen many people do more than one spiral. Any advice or ideas on that? I do realise the speed has to double or triple. Getting rid of the magnifying glass with a large image would make it look really cool. Plus you get the nice drum behind the Nipkow disc.

CheersKeith

Yes that's a good idea.. i know Holtzman did a 2 spiral 60 line with a interrupter bit like the 2 drum monitor ...apart from that only bit of talk .To get true size with a mechanical monitor either you have to make it bigger or have more light to project to ...or have a 2 drum or disk idea .Yes it depends on number of slits or holes half the number twice as fast so on ,its a toss up between size wanted and speed you can do and line number ..With your laser you could cut fine nice line or holes ...i had to do mine with a Stanley knife and black light proof paper...you could sure do better than that a 2 disk monitor would be a lot easier if you don't mind the line curve .....drum you get the correct look for size i am sure the curve would show up on a disk version worse than a Nipkow ...having said that i wouldn't mind seeing one always had in mind to try it .There's lots of versions of what you have in mind google patents give you a good idea of what has been tried if you want to look i have a lot of file ...so you planning a Drum disk idea i would say i would go slits instead of a Nipkow one you can go multi system for a start if you are going to the trouble of a 2 motor version .I would make the framing motor always a stepper due to the slower speed and keep the line disk or drum DC for the high speed needed ...also if you go this way a pulley system for the line side of it you get extra speed out of your dc motor for higher line rates ,Doms software does 30 32 48 60 64 line and the new software up to the low 100's any line rate you want what better way to test the mechanical monitors limits !

The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.

I have not really measured the smallest holes I can do but my experience with my laser machine would suggest around 0.3mm would be about the limit. I guess if I got a special lens then that could be halved to 0.15 but the lens is quite expensive.Since I got my laser cutter my drill press and bandsaw kinda sit there a lot these days.

I have some 7.5 degree steppers in stock as that seems to be the perfect step size for dual motor framing. I also really like the idea of mechanical gearing as it matches the period better. But I guess it is noisy and hard to do. I kind of like the idea of drum and disc as it shows off two technologies at once.

On another note, I need to catch up on my work a bit as these old TV's have really distracted me for the last two months. Totally fascinating.

I have not really measured the smallest holes I can do but my experience with my laser machine would suggest around 0.3mm would be about the limit. I guess if I got a special lens then that could be halved to 0.15 but the lens is quite expensive.Since I got my laser cutter my drill press and bandsaw kinda sit there a lot these days.

Cutting the holes could not be easier with that thing you could go very small great for a camera if you ever want to try or a higher line rate nipkow monitor .

I have some 7.5 degree steppers in stock as that seems to be the perfect step size for dual motor framing. I also really like the idea of mechanical gearing as it matches the period better. But I guess it is noisy and hard to do. I kind of like the idea of drum and disc as it shows off two technologies at once.

i will look forward to that design lots of different mechanical monitors have been done in the past a drum disk would be great to see...and yes that stepper will come in handy bipolar unipolar either are fine

On another note, I need to catch up on my work a bit as these old TV's have really distracted me for the last two months. Totally fascinating.

CheersKeith

[/quote]

Yes the real world gets in the way of the fun i agree !

The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.

Keith and I have been doing a bit of back-and-forth on improvements to the software, and Keith has found a lot of optimisations.Meanwhile, I've had a chance to film the first video that he converted, and thought I'd place it up here for comparison between the displays of the two televisors.

Your browser does not support the html5 video tag.

I didn't have the video sound running - but if you hear odd sound in the background, that's a 3D printer sitting next to the 'visor.